<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        body{
            background-color: #000;
            overflow: hidden;
        }

        .sun{
            width: 100px;
            height: 100px;
            position: absolute;
            left:50%;
            top:50%;
            transform:translate(-50%,-50%);
            background-color: yellow;
            box-shadow: 0 0 30px 3px gold;
            border-radius: 50%;
        }

        .earth{
            width: 350px;
            height: 350px;
            position: absolute;
            left:50%;
            top:50%;
            /* 保证居中*/
            transform:translate(-50%,-50%);
            border: 1px solid #ccc;
            border-radius: 50%;

            /*animation: rot 8s linear infinite;*/
        }

        .earth::before{
            content:"";
            width: 40px;
            height: 40px;
            position: absolute;
            left:0;
            top:50%;
            transform:translate(-50%,-50%);
            background-color: dodgerblue;
            border-radius: 50%;
        }

        .moon{
            width: 80px;
            height: 80px;
            position: absolute;
            left:0;
            top:50%;
            transform:translate(-50%,-50%);

            border-radius: 50%;
            animation: rot 2s linear infinite;
        }

        .moon::before{
            content:"";
            width: 15px;
            height: 15px;
            position: absolute;
            left:0;
            top:50%;
            transform:translate(-50%,-50%);
            background-color: #fff;
            border-radius: 50%;
        }

        .venus{
            width: 500px;
            height: 500px;
            position: absolute;
            left:50%;
            top:50%;
            transform:translate(-50%,-50%);
            border: 1px solid #ccc;
            border-radius: 50%;

            animation: rot 6s linear infinite;
        }

        .venus::before{
            content:"";
            width: 30px;
            height: 30px;
            position: absolute;
            left:0;
            top:50%;
            transform:translate(-50%,-50%);
            background-color: red;
            border-radius: 50%;
        }

        .mars{
            width: 600px;
            height: 600px;
            position: absolute;
            left:50%;
            top:50%;
            transform:translate(-50%,-50%);
            border: 1px solid #ccc;
            border-radius: 50%;

            animation: rot 10s linear infinite;
        }

        .mars::before{
            content:"";
            width: 50px;
            height: 50px;
            position: absolute;
            left:0;
            top:50%;
            transform:translate(-50%,-50%);
            background-color: pink;
            border-radius: 50%;
        }

        @keyframes rot {
            0%{
                transform:translate(-50%,-50%) rotate(0deg);
            }
            100%{
                transform:translate(-50%,-50%) rotate(360deg);
            }
        }
    </style>
</head>
<body>
    <div class="sun"></div>
    <div class="earth">
        <div class="moon"></div>
    </div>
    <div class="venus"></div>
    <div class="mars"></div>
</body>
</html>